Fluorescent X-ray analyzer

Abstract

A fluorescent X-ray analyzer includes a detector ( 6 ) for detecting fluorescent X-rays ( 5 ) emitted from a sample piece ( 1 ) to be analyzed, and a first collimator ( 10 ) disposed between the sample piece ( 1 ) and the detector ( 6 ) supported for movement between inserted and retracted positions with respect to a path of travel of the fluorescent X-rays ( 5 ) towards the detector ( 6 ). The first collimator ( 10 ) comprises a wall ( 11 ) adjacent the sample piece ( 1 ) that is stepped to provide stepped wall segments ( 11 a, 11 b, 11 c ) having respective apertures ( 12 a, 12 b, 12 c ) of varying diameters defined therein. The smaller the aperture, the closer it is to the sample piece ( 1 ) when one of the apertures ( 12 a, 12 b, 12 c ) is selected according to a size of a target area of the sample piece ( 1 ) to be measured and is then brought in register with the path of travel of the fluorescent X-rays ( 5 ) towards the detector ( 6 ).

What is claimed is:  
     
       1. A fluorescent X-ray analyzer which comprises: 
       a detecting means for detecting fluorescent X-rays emitted from a sample piece to be analyzed; and  
       a first collimator disposed between the sample piece and the detecting means and supported for movement between inserted and retracted positions with respect to a path of travel of the fluorescent X-rays towards the detecting means;  
       said first collimator comprising a wall adjacent the sample piece that is stepped to provide stepped wall segments having respective apertures of varying diameters defined therein, the smaller the aperture, the closer it being when one of the apertures is selected according to a size of a target area of the sample piece to be measured and is then brought in register with the path of travel of the fluorescent X-rays towards the detecting means.  
     
     
       2. The fluorescent X-ray analyzer as claimed in  claim 1 , wherein the first collimator comprises a substrate and a projection formed on the substrate, said projection having a tip where the stepped wall segments are formed. 
     
     
       3. The fluorescent X-ray analyzer as claimed in  claim 1 , further comprising a second collimator disposed between the first collimator and the detecting means and supported for movement between inserted and retracted positions with respect to the path of travel of the fluorescent X-rays towards the detecting means, said second collimator having one or more apertures of a diameter larger than that of any one of the apertures in the first collimator. 
     
     
       4. The fluorescent X-ray analyzer as claimed in  claim 1 , further comprising a drive mechanism for moving the sample piece to an optimum position at which a radiation intensity of primary X-rays towards a target area of the sample piece to be measured can be maximized depending on the size of the target area of the sample piece, and wherein the apertures in the first collimator are arranged so as to encompass the target area of the sample piece as viewed from the detecting means. 
     
     
       5. A fluorescent X-ray analyzer which comprises: 
       an X-ray source for emitting primary X-rays to a sample piece to be analyzed;  
       a detecting means for detecting fluorescent X-rays emitted from a sample piece; and  
       a first collimator disposed between the sample piece and the detecting means, said first collimator having a plurality of apertures defined therein, and having a flat wall adjacent the sample piece, at least a portion of said flat wall being positioned within an area of irradiation of the primary X-rays, and a shielding wall, disposed downstream of said first wall, for preventing the primary X-rays from entering a path of travel of the fluorescent X-rays from the side of the detecting means of the wall adjacent the sample.  
     
     
       6. The fluorescent X-ray analyzer as claimed in  claim 5 , further comprising a second collimator supported for movement between inserted and retracted position with respect to the path of travel of the fluorescent X-rays, said second collimator having one or more apertures of a diameter larger than that of any one of the plural aperture in the first collimator. 
     
     
       7. The fluorescent X-ray analyzer as claimed in  claim 5 , further comprising a drive mechanism for moving the sample piece to an optimum position at which a radiation intensity of a primary X-rays towards a target area of the sample piece to be measured can be maximized depending on the size of the target area of the sample piece, and wherein the apertures in the first collimator are arranged so as to encompass the target area of the sample piece as viewed from the detecting means. 
     
     
       8. A fluorescent X-ray analyzer which comprises: 
       an X-ray source for emitting primary X-rays to a sample piece to be analyzed;  
       a detecting means for detecting fluorescent X-rays emitted from a sample piece to be analyzed; and  
       a first collimator disposed between the sample piece and the detecting means, said first collimator comprising a flat wall adjacent the sample piece and having a plurality of apertures defined therein, and a shielding portion provided at a front side of said flat wall and extending forwardly of the apertures for preventing primary X-rays, generated by the X-ray source, from entering any one of the apertures.  
     
     
       9. The fluorescent X-ray analyzer as claimed in  claim 8 , further comprising a sample table for supporting the sample piece thereby and wherein said first collimator is arranged so as to receive fluorescent X-rays in a direction inclined relative to the sample table, said first collimator having a corner area confronting the sample table, said corner area being cutout to define a cutout surface parallel to a surface of the sample table. 
     
     
       10. The fluorescent X-ray analyzer as claimed in  claim 8 , wherein said shielding portion is either a visor formed integrally with the first collimator or a visor formed by fitting a separate plate to the first collimator. 
     
     
       11. The fluorescent X-ray analyzer as claimed in  claim 10 , wherein the visor of the first collimator has an extension which is formed with a primary X-ray aperture. 
     
     
       12. The fluorescent X-ray analyzer as claimed in  claim 8 , wherein said shielding portion is arranged to incline in a direction in which a portion of the wall adjacent the sample piece close towards the X-ray source approaches a center axis of the X-ray source. 
     
     
       13. The fluorescent X-ray analyzer as claimed in  claim 8 , further comprising a second collimator supported for movement between inserted and retracted position with respect to the path of travel of the fluorescent X-rays, said second collimator having one or more apertures of a diameter larger than that of any one of the plural aperture in the first collimator. 
     
     
       14. The fluorescent X-ray analyzer as claimed in  claim 8 , further comprising a drive mechanism for moving the sample piece to an optimum position at which a radiation intensity of primary X-rays towards a target area of the sample piece to be measured can be maximized depending on the size of the target area of the sample piece, and wherein the apertures in the first collimator are arranged so as to encompass the target area of the sample piece as viewed from the detecting means. 
     
     
       15. A fluorescent X-ray analyzer which comprises: 
       a detecting means for detecting fluorescent X-rays emitted from a sample piece to be analyzed; and  
       a first collimator comprises a plate member having a plurality of apertures defined therein and supported for movement between inserted and retracted position with respect to a path of travel of fluorescent X-rays; and  
       a second collimator disposed between the first collimator and the detecting means and comprising a plate member having apertures defined therein of a diameter larger than that of the apertures in the first collimator, said second collimator being supported for movement between inserted and retracted position with respect to the path of travel of the fluorescent X-rays.  
     
     
       16. The fluorescent X-ray analyzer as claimed in  claim 15 , further comprising a drive mechanism for moving a sample piece to an optimum position at which a radiation intensity of primary X-rays towards a target area of the sample piece to be measured can be maximized depending on the size of the target area of the sample piece, and wherein the apertures in the first and second collimators are arranged so as to encompass the target area of the sample piece as viewed from the detecting means.